Effect of Patient Financial Incentives on Statin Adherence and Lipid Control: A Randomized Clinical Trial

“Initially, eligibility was limited to individuals with diabetes, LDL-C level greater than 130 mg/dL (to convert LDL-C to mmol/L, multiply by 0.0259), and an annual statin medication possession ratio in pharmacy records of less than 80%. We subsequently broadened eligibility criteria to include individuals with a statin prescription who self-reported nonadherence and had either (1) LDL-C level greater than 100 mg/dL and a diagnosis of ASCVD or an American College of Cardiology/American Heart Association Task Force 10-year cardiovascular disease risk score of at least 7.5%, or (2) LDL-C level greater than 190 mg/dL with no other risk factors, or (3) both.

[..] we invited 13,235 individuals to create accounts on the Way to Health website. [..] A total of 851 participants were eligible, consented, and were mailed electronic pill bottles.

[..] In addition to electronic pill bottles, all participants in all groups received daily reminders to take their statin via text message, automated telephone call, or email per participant preference. Providing reminders to all participants was a deliberate design choice, permitting an analysis that could isolate the effect of financial incentives from messaging because the intervention groups would necessarily receive daily feedback about whether they earned financial incentives. The default reminder time was 10:00 pm, but participants could choose an earlier time before randomization. All participants received up to $200 for completing study milestones, including enrollment and LDL-C measurements at baseline and at 6 and 12 months. The control group received no further intervention. Over a 6-month period, individuals in the 3 intervention groups were eligible for financial incentives based on their measured adherence. We delivered incentives as a sweepstakes to make use of people’s tendency to overestimate small probabilities. On days when patients were nonadherent, we also invoked loss aversion through messages about the reward that they missed. Participants in the intervention groups were informed about their earnings the following day.

Each participant was assigned a 2-digit number. Every day, a random 2-digit number was generated by Way to Health and compared with the participants’ assigned numbers to determine the size of the financial incentives. A fully adherent participant in a financial incentives group could expect to earn, on average, $2.80 per day or $504 total through the 180-day intervention period.

Simple sweepstakes – If both digits matched (1 in 100 probability), an adherent participant received $100. If 1 digit matched (18 in 100 probability), an adherent participant received $10.
Deadline sweepstakes -The incentive was identical to simple sweepstakes if the participant took their statin before their daily reminder. If the participant took their statin after receiving the reminder, the incentive was halved to $50 for a 2-digit match and $5 for a 1-digit match.
Sweepstakes plus deposit contract – Participants were eligible for daily sweepstake rewards, but with half the expected monetary value of simple sweepstakes. In addition, on the first day of each 30-day month, $45 was deposited into a virtual monthly account. Deductions of $1.50 were made each day that a participant was nonadherent. The amount remaining was paid at the end of the month and the deposit reset to $45 for the next month.

[..] Over the 6-month intervention period, the mean per-patient incentive payments were $414.84 for the simple sweepstakes group, $384.24 for the deadline sweepstakes group, and $465.42 in the sweepstakes plus deposit contract group. Measured adherence at 6 months (ie, the proportion of 180 days with electronic pill bottle opening) in the control group (0.69; 95% CI, 0.66-0.72) was lower than that in the simple sweepstakes group (0.84; 95% CI, 0.81-0.87), the deadline sweepstakes group (0.86; 95% CI, 0.83-0.89), and the sweepstakes plus deposit contract group (0.87; 95% CI, 0.84-0.90) (P < .001 for each incentive group vs the control group).

[..] At baseline, the mean (SD) LDL-C level was 143.2 (42.5) mg/dL. At 12 months, mean LDL-C reductions from baseline were substantial and similar across all groups: 33.6 mg/dL (95% CI, 28.4-38.8 mg/dL) in the control group, 32.4 mg/dL (95% CI, 27.3-37.6 mg/dL) in the simple sweepstakes group, 33.2 mg/dL (95% CI, 28.1-38.3 mg/dL) in the deadline sweepstakes group, and 36.5 mg/dL (95% CI, 31.3-41.7 mg/dL) in the sweepstakes plus deposit contract group (Holm-Bonferroni adjusted P > .99 for each incentive group vs the control group).

[..] In this randomized clinical trial testing the effects of carefully designed rewards to promote habit formation in statin adherence, financial incentives improved measured adherence but did not improve LDL-C levels compared with a control group. We used insights from economic theory, management, and psychology to test 3 behavioral incentive interventions. The first group received simple daily incentives to instill automaticity. To produce a self-initiated health routine, participants in a second group received a full incentive for taking the statin before a daily reminder and a reduced incentive if the statin was ingested after the reminder. The third combined a hybrid sweepstakes plus deposit contract, emphasizing loss aversion. We found that the simple financial incentives led to comparable effects on measured adherence and LDL-C level changes as the more complex interventions. In designing the trial, we hypothesized that statin adherence would be a context in which the instant gratification provided by salient financial incentives could be impactful because statins convey no immediate, perceptible benefits to most patients. Instead, the health benefits are distant and diffused in the future. Given this strong theoretical basis for using financial incentives to promote medication adherence, careful consideration should be given as to why none of the incentives improved LDL-C level over the control group. The results give rise to important considerations in the pressing research agenda to induce positive and lasting changes in health behavior using time-limited interventions.

First, we draw attention to the fact that participants were at high risk for ASCVD events, were already prescribed statins, and were recruited after a clinical encounter showing elevated LDL-C levels. Most were receiving care within an academic health system. Notably, they had high adherence during the trial, as measured by opening of electronic pill bottles, across all study groups. Most high-risk individuals presenting with high LDL-C levels in a health system would be expected to receive usual care interventions and counseling to lower their cholesterol. Both control participants and eligible non-enrolled patients achieved clinically meaningful reductions in LDL-C levels that were comparable to the reductions in the intervention groups at the conclusion of the 12-month study. Given that eligibility relied on suboptimal LDL-C levels recently measured in usual care, clinicians may already have been active in intensifying the dose or the type of statin and encouraging healthful behavior concurrent with the trial. Mean reversion can also explain some of the LDL-C improvement. Taken together, these observations suggest that although financial incentives did not reduce LDL-C levels in this population of patients, financial incentives could still be a useful intervention for patients with lower degrees of health engagement who do not use or have access to primary care. This is especially possible because the effect of statins on LDL-C reduction at the start of medication regimens is substantial and well-documented.

Second, our data present the possibility that financial incentives improved adherence, but that this better statin adherence did not lead to greater improvements in LDL-C levels vs control. To explore this idea, we used values from the first 6 months of adherence data when the interventions were in effect. Over that period, for the same level of measured adherence, the controls tended to have better change in LDL-C level than those in the incentive groups. This discordance between measured adherence and LDL-C level between intervention and control patients could be explained if financial incentives led participants to neglect other health-related behaviors that affect cholesterol, such as diet and exercise. Another possibility is that control participants, who did not receive incentives for adherence, took their medication from other pill bottles, leading to a potential upward bias in the estimated difference in adherence across groups.

Third, given the high adherence even in the control group, the marginal adherence gain among intervention groups may have generated only a small effect on LDL-C level. Although adherence was a secondary outcome here, and electronic pill bottle data are an improvement over self-reported adherence data or medication refill rates, our study reinforces the imperative to go beyond adherence and instead focus, as was done in this trial, on the health outcomes or validated surrogate outcomes of primary interest. This is particularly salient because ASCVD is the primary cause of death in the US, and a major public health priority is to lower its incidence by better managing the associated risk factors.”

Full article, Barankay I, Reese PP, Putt ME et al. JAMA Network Open 2020.10.9